Epitope Sequences in Dengue Virus NS1 Protein Identified by Monoclonal Antibodies

Abstract

Dengue nonstructural protein 1 (NS1) is a multi-functional glycoprotein with essential functions both in viral replication and modulation of host innate immune responses. NS1 has been established as a good surrogate marker for infection. In the present study, we generated four anti-NS1 monoclonal antibodies against recombinant NS1 protein from dengue virus serotype 2 (DENV2), which were used to map three NS1 epitopes. The sequence 193 AVHADMGYWIESALNDT 209 was recognized by monoclonal antibodies 2H5 and 4H1BC, which also cross-reacted with Zika virus (ZIKV) protein. On the other hand, the sequence 25 VHTWTEQYKFQPES 38 was recognized by mAb 4F6 that did not cross react with ZIKV. Lastly, a previously unidentified DENV2 NS1-specific epitope, represented by the sequence 127 ELHNQTFLIDGPETAEC 143 , is described in the present study after reaction with mAb 4H2, which also did not cross react with ZIKV. The selection and characterization of the epitope, specificity of anti-NS1 mAbs, may contribute to the development of diagnostic tools able to differentiate DENV and ZIKV infections.

Flavivirus Cross-Reactivity to Dengue Nonstructural Protein 1 Antigen Detection Assays

“…This may explain the cross-reactivity observed among different flaviviruses in our evaluation, especially for undesired viruses at high pathogen/RNA loads. It is known that monoclonal antibodies react with different epitope regions on NS1 [31] and these regions are of variable length and amino acid composition. Since sNS1 commercial assays tend to use different antibodies that may target nonidentical epitopes, cross-reactivity can be variable among flaviviruses, as observed in the present study.…”

Production of Immunologically Active Untagged Recombinant DENV-2 NS1 in Escherichia coli

“…The accession number of each amino acid sequences used in the alignment are as followed: this study (ADK37478), Indonesia (AHK09923), Malaysia (CAZ72152), Singapore (ABW82013), New Guinea (AAC59275) and Thailand (P29990). The conformational epitopes are based on DENV2-NS1 epitope study conducted by Rocha et al (2017) Further analysis of antigenicity of refolded DENV2-NS1 protein was conducted using ELISA. The DENV-2 NS1 protein gave a high value of A 450 which was interpreted as a reactive protein to anti-NS1 monoclonal antibody (Fig.…”

“…The result of these antigenic tests corroborated that sequence-specific structures or the conformational epitopes which contributed to the antigenicity of DENV-2 NS1 protein were present on the surface of the protein. These conformational epitopes are 25 VHTWTEQYKFQPES 38 , 127 ELHNQTFLIDGPETAEC 143 , 193 AVHADMGYWIESALNDT 209 and located in three different regions of protein 3D structure (PDB ID: 4O6B) (Rocha et al, 2017). The first epitope is located in an external loop, the second one is located in beta-sheets in an external region and the third one is located in betasheets in an internal region (Rocha et al, 2017).…”

Febrile temperatures increase in vitro antibody affinity for malaria and dengue antigens

“…To this end, we made use of antigens from a viral agent, i.e. non-structural protein 1 (NS1) from dengue virus serotype 2 DENV-2 (8), and from a protozoan pathogen, namely the 19-kDa carboxyterminal region of merozoite surface protein 1 (MSP1 19 ) from Plasmodium vivax (9), and their corresponding monoclonal IgG antibodies (10,11).…”